question_answer

Samantha, Jessica and Roseline begin to jog around a circular stadium. They complete their revolutions in 84 s, 56 s and 63 s respectively. After how many seconds will they be together at the starting point?

A)  336                 

B)         504

C)  252                 

D)         Cannot be determined

Correct Answer: B

Solution :

\[\therefore \] \[LCM=2\times 2\times 2\times 3\times 3\times 7=504\] Hence, they will meat after 504 s.